Polypyrazolone pigments



United States latent Ofilice herewith. Inv general, such bis pyrazolones are made by reaction of one mole of a bis-keto ester of the formula with two moles of a hydrazine of the formula RNH-NH wherein X and R have the values given above and R 10 is lower alkyl such as methyl, ethyl or the like. This reaction to form the bis pyrazolone is carried out at elevated temperatures and may, if desired, be catalyzed with glacial acetic acid or the like, and may be carried out in a solvent or diluent such as ethanol, dioxane or the like, etc. As some specific examples of bis-keto esters which may be employed in making the his pyrazolones, there may be mentioned the methyl and ethyl esters of the 4,4'-bisacetic acids derived from diphenyl ether and diphenyl 2,993,451 POLYPYRAZOLONEPIGMENTS Carl Mayn Smith, White Bear Lake, Minn., assignor to General Aniline & Film Corporation, New York, N.Y., a corporation of Delaware No Drawing. Application December 23, 1957 Serial No.704,236 10 Claims. (Cl. 260-240) This invention relates to novel polypyrazolone pigments 5 and to methods for producing same. More particularly, the pigments of the instant invention are compounds de/ void of sulfonic and carboxylic acid groups having the is 1 l t wherein X is selected from the group consisting of'O and 1 AS examples of hydrazineS which y be employed in S; and R is selected from the group consisting ofI-I, lower making the his Pyrazolohes, there y be mentioned th alkyl, aralkyl and aryl. It has been found that the above. m hy y isobutyl, y zy ph nyl, p-bromodescribed novel compounds comprise a group of oiland phenyl, bi'phenyl, o-nitrophenyl, m-nitrophenyl, p-nitrowater-insoluble pigments having improved, fastness and P y p yh yh y P- y y y other properties which render them highly suitablefor use p hyl and 2-naph-thy hydraZineS n the l ein inks, natural and synthetic resins, rubber, paints, lac- Th above -k esters y in general be p p quers, enamels, and other film-forming compositions, in by. reacting the appropriate diacid chloride (dicarbonyl pigmentation of fibers and filmsby incorporationir to the chloride) of the corresponding diphenyl ether or diphenylspinning solutiongjn paper and in other common pigment sulfide With methyl or ethyl acetoacetate in cold aqueous applications. J alkali in essentially a Schotten-Baumann type procedure, In the above formula, R may be H, lower alkyl such as y diace'tylathlg the diphfinyl Sulfide y a Friedel' methyl, ethyl, butyl, .isobutyl, amyl, isoamyl and the, like, 9 .Crafts reaction and then condensing the resulting diketone aralkyl, such as benzyl, and aryl such asphenyl, .1- (diacetyl derivative) with diethyl carbonate. naphthyl, z-naphthyl and biphenyl and the lik yand inert As is well recognized in the dyestuif and pigment art, substituted derivatives thereof. Examples of inert sub improved Pigmentary PTOPMties Obtained W thfl stituents mentioned above include'halo such as chloro and al a t ts are as pure as possible Thus, improved bromo, nitro, alkyl such as methyl and ethyl, phenyl and results are obtained when the bis-pyrazolone reactant is th like, first purified, as for example, by recrystallization from an The compounds of the above formula may be prepared organic solvent such as dichlorobenzene, trichlorobenzene by reacting two molecular equivalents of a his pyrazolone Oli e li having the formula Still further improved pigmentary properties are obtained when the above described polypyrazolone pigments of the instant invention are further purified by fractional f precipitation in sulfuric acid, comprising dissolving the pigment in concentrated sulfuric acid, diluting with small N N amounts of water to form a precipitate, presumably the sulfate salt, separating the precipitate by filtration and regenerating the pure pigment by slurrying in water. Optimum results are obtained when this treatment is carried out in a closed vessel or with exclusion of atmospheric humidity. The pigments so obtained are of still 0 further improved brightness, strength and light-fastness.

1 The pigments of the instant invention may be employed as such or prepared for the market in known manner de carboxylate such as diethoxyr'nethylacetatei Pending p intended thereof. Thus, 21 ph (3) H ti th bi pyrazolone ith an te f th sentative paste stutable for use in inks, paints and the like formic acid such as ethylorthoformate, preferably in y be made y ball-milling the pigment Paste obtamed glacial a eti a id, as described hereinabove for a number of hours with 50% (4) H i th bi pyrazglone ithyf m id of Tamol NNO (sodium salt of sulfonated naphthalene ,The above mentioned bis pyrazolone s employed as reformaldehyde Condensate) 011 g e g of plgmelltactants in the above described processes, and their meth- In the following examples, parts are y We1ght unless ods of production are disclosed and claimed in my co- Otherwise indicated, Parts y Weight are In grams and pending application Serial No. 704,318 filed on even date a parts by volume are in cc. These examples are illuswherein X and R have the values given above, with one molecular equivalent of a methylidyne donor linking agent. The following methods may be employed? (1) 'Heatingan alkaline-solution of the'bis pyrazrolor'1e with chloroform. (2) Heating the bis pyrazolone with dialkoiiymethyl 2,903,451 3 4 trative of the instant invention and are not to be regarded as limitative. parts by weight of the above bis-pyrazolone (prepared as described in Example 6 of my said copending application), and 3.3 parts by volume ethyl orthoformate is heated under agitation at 90 C. for 50 minutes and then at 100 C. for 30 minutes. The yellow pigment is filtered off at room temperature, washed with acetone and dried. It has the structural formula EXAMPLE 1 Preparation of pigment from 1,1-diphenyl-3,3-(diphenyl ether-4,4)-5,5-dipyrazl0ne In a 2 liter flask is charged a ball milled slurry of g. of the above his pyrazolone (prepared as described in Example 2 of my said copending application) with 200 cc.

formamide. 600 cc. additional formamideris used for 25 rinsing the balls and charged to the flask. The mixture is heated as rapidly as possible with a Meeker burner on a tripod to reflux, reflux beginning at about 165 C., and rising to 195 C. The pigment begins separating before all of the his pyrazolone is in solution. After refluxing for 12 minutes the thickness of the mixture does not increase nor the appearance of the mixture in bulk. It is filtered at the boil on a number 54 Watman paper, washed of h Pigmmt prepared as described in Example 1 The with. hot formamideuntil the wash is free of color, then charge Stirred, hour to dissolve the pigment.

washed with acetone. The acetone wash at first is very I a dark colored and the pigment brightens considerably.- Then under cfmhng below 25 parts by Flume H 50 1s gradually v added lowering the acidity to When the acetone wash is colorless, the cake is then washed free of acetone with hot water, since a small test 89% H 50 The charge is agitated for 1 hour. The precipitate is filtered oil? on a glass sinter funnel and shows that the pigment does not dry to a soft powder.;

The empmcal formula 15 C51H42O6N8 washed with 25 parts by volume 89% H 80 Then the cake is introduced into 300 parts by weight, ice and water, stirredforv one half hour, filtered, washed neutral and EXAMPLE 3 A-ftertreatment of pigment A flask equipped with a cooling bath, a thermometer, an agitator and a calcium chloride tube to prevent atmospheric moisture from entering is charged with parts by volume concentrated sulfuric acid (96%). Under. cooling below 25 C. there is added gradually, 6 g.

Calcd. Found Percent C 74,43 7M2 45 dried. There is obtained 52 parts by weight of a yellow $33232 ii}, &5; pigment which is brighter than the product of'EXample 1.

This invention has been disclosed with respect to cer-' The pigment has the formula tainpreferred embodiments, and there will become obvious to persons skilled in the art various modifications, equivalents andvariations thereof which are intended to be included within the spirit and scope of this invention.

1 claim: 1. A compound having the formula EXAMPLE 2 Preparation of pigment from 1,1 '-diphenyl-3,3'-(diphenyb sulfide-4,4)-5,5'-dipyraz0lone A charge of 30 parts by volume glacial acetic acid, 10

o=$ A. v I! wherein X is selected from the group consisting of O and S; and R is selected from the group consisting of H,

lower alkyl, benzyl, phenyl, naphthyl, biphenyl and the halo, nitro and lower alkyl substituted derivatives thereof.

2. The compound of the formula 3. The compound of the formula 4. A process for producing a compound as defined in claim 1 comprising reacting by heating 2 moles of a his pyrazolone having the formula II N wQ Q-re-w O=C N II II I N 7. A process for producing a compound as defined in claim 2 comprising reacting by heating 2 moles of 1,1'-diphenyl-3,3'-(diphenylether-4,4) 5,5 dipyrazolone with one mole of formamide.

8. A process for producing a compound as defined in claim 2 comprising reacting by heating 2 moles of 1,l-diphenyl-3,3'-(diphenylether-4,4') 5,5 dipyrazolone with one mole of ethyl orthoformate.

9. A process for producing a compound as defined in claim 3 comprising reacting by heating 2 moles of 1,1'-diphenyl-3,3'-( diphenyl sulfide-4,4)-5,5-dipyrazolone with one mole of ethyl orthoformate.

10. A process as defined in claim 4 followed by purification of the resulting compound by dissolving same in concentrated sulfuric acid and hydrolyzing the result ing sulfate ester of said compound by treatment with water.

References Cited in the file of this patent UNITED STATES PATENTS Dent Dec. 12, 1950 OTHER REFERENCES Ridi et al.: Gazz. Chim. Ital, vol. 83, pp. 36-43 (1953).

Venkataraman: Synthetic Dyes, vol. II, p. 1150 (Academic Press Inc., 1952). 

1. A COMPOUND HAVING THE FORMULA 